UrlReduceStrategy.java

/*
 * Copyright 2010 Ronnie Kolehmainen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.github.cssxfire.filter;

import com.github.cssxfire.tree.CssDeclarationPath;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.vfs.VirtualFile;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * <p>Reduces the candidates down to the elements in files that matches the given url. If the collection is
 * empty this reducer does nothing.
 * <p><p>
 * Created by IntelliJ IDEA.
 * User: Ronnie
 */
public class UrlReduceStrategy implements ReduceStrategy<CssDeclarationPath> {
    private static final Logger LOG = Logger.getInstance(UrlReduceStrategy.class.getName());

    @NotNull
    private final String url;

    public UrlReduceStrategy(@NotNull String url) {
        this.url = url;
    }

    public void reduce(@NotNull Collection<CssDeclarationPath> candidates) {
        if (LOG.isDebugEnabled()) {
            LOG.debug("Reducing " + candidates.size() + " candidates for url: " + url);
        }
        if (candidates.isEmpty()) {
            // nothing to do here
            return;
        }

        List<CssDeclarationPath> matches = new ArrayList<CssDeclarationPath>();
        for (CssDeclarationPath candidate : candidates) {
            VirtualFile file = candidate.getFileNode().getVirtualFile();
            if (file != null && url.equals(file.getUrl())) {
                // candidate file url matches routed file
                matches.add(candidate);
                if (LOG.isDebugEnabled()) {
                    LOG.debug("  Match: " + candidate);
                }
            }
        }

        candidates.retainAll(matches);
    }
}